Despite evidence pointing to excessive mortality, emergency room visits and hospitalizations for asthma among inner city black and Hispanic children, little is known regarding the risk factors for these differences, nor are there feasible plans to change this pattern. As part of a National co- operative Inner City Asthma Study, we therefore propose the following studies. In Phase I, a case-control study will compare 75 inner city black asthmatic children aged 4-11 years to control groups of 75 each of inner city black children without asthma, and asthmatic and nonasthmatic children in an urban middle class environment. They will be compared in terms of: demographics, allergy, disease severity (methacholine sensitivity), home environment (allergen concentration and variety, smoking frequency and child's urinary cotinine levels), general health status, and psychosocial factors affecting health care utilization (crowding, alcohol and substance abuse, psychosocial functioning, family interactions). Pilot studies will be conducted in year 2 to develop effective home nursing visit methods to reduce home environmental allergens and cigarette smoking. Another pilot study will demonstrate the feasibility of long term careful monitoring of disease severity in this inner city black population applying methods currently in use in our study of the effects of immunotherapy on childhood asthma (AI:21073). In Phase II, we will mount a prospective controlled trial to test the effectiveness of environmental allergen and household smoking elimination by home nursing visits on asthma disease severity and morbidity. Eighty inner city black asthmatic children will be evaluated in terms of relevant disease and psychosocial history, allergy skin tests, serum IgE antibody, methacholine challenge and urine cotinine levels. Using daily symptoms and PEFR, medications will be carefully adjusted to optimally treat their asthma. After 3 month's stabilization, they will be randomized to receive advice in the medical center regarding environmental management or to receive support from home nursing visits. During a one year period of observation, the effect of these environmental interventions in the two groups will be compared in terms of medication requirements, school absenteeism, emergency room visits and hospitalizations.